What Is Hair Porosity & How Do You Know What Type You Have?

For those of you who have found yourselves scrolling through #hairtok in search of growth tips or thickening treatments, no matter your texture —straight, wavy, curly, or coily — chances are you’ve come across the phrase “hair porosity.” Whenever there’s talk of a wash day or shower routine, porosity seems to be at the forefront of conversations surrounding hair health. However, for those of us who aren’t experts, what is hair porosity? And what is its relationship to our strands?

At first, you might feel intimidated by the scientific-sounding name, but hair porosity simply describes how well your hair holds onto moisture. If you have low porosity, your hair will take longer to absorb water while high porosity hair gets wet easily.  Understanding this fact about your strands can be really important in properly developing a routine that yields strengthening and nourishing results.

Still in need of more information? TZR has tapped two trichologists to give you the breakdown of everything you should know about the technical beauty term. Below, you’ll find all the expert-given details about determining and addressing your hair porosity. Plus, tips on what products you should be incorporating into your regimen and ingredients to avoid.

What Is Hair Porosity?

As mentioned above, hair porosity revolves around how well your strands can both soak up and preserve moisture. Kimberlee Blakely, trichologist at The Mane Choice, says that this is impacted by the structure of the outmost layer of your hair, the cuticle layer, which decides how well water, oils, and other moisturizing products can penetrate your hair shaft. She adds that textured hair is most noted for having varying porosity levels across different strands which can influence how natural hair responds to treatments.

This begs the big question of whether you are able to fix or alter your porosity. And, according to Monique Rapier, a trichologist, influencer, and V&Co. Beauty brand ambassador, because this phenomenon is majorly established by genetics, you cannot permanently change your porosity from low to high and vice versa. However, through your weekly practices and customs, there are methods of improving your porosity or managing it in a way that is conducive to lively, robust hair.

“What is most important when choosing a routine is to make sure you listen to your hair and pay attention to how it reacts to the product,” says Blakely. The first step, though, is determining which category you fall under.

How Do You Determine Your Porosity?

Both trichologists agree that the best way to determine your porosity is the “glass of water test.” After cleaning your hair, removing all product, and letting it dry, take a glass of water and drop a single strand into the cup. If the strand floats before sinking, you most likely have low porosity. If the strand hovers in the middle of the glass, your porosity is probably somewhere between low and high. And, if it rapidly sinks to the bottom, then it is likely that you have high porosity.

Alternatively, Blakely says that you can opt for feel-testing. Those with rough strands can link it to having a higher porosity while smoothness can signal lower levels. But, Blakely says that she wants you to remember that figuring out where you fit in isn’t black and white.

“The challenge with addressing porosity is that you can have different high and low porosity hair throughout the same head,” says Blakely. “Depending on how you style your hair, each individual strand can have a different porosity as well.”

What Is Low Porosity Hair?

If the water test brought you towards low porosity hair, this means that your cuticles are tightly packed together, Rapier says. This is what makes it more difficult for your strands to absorb hydration. Blakely adds that this hair type will repel water which can make your moisturizing formulas feel like they’re sitting on the surface instead of being drawn in. Because of these factors, she says that wash days should be more limited because despite its difficulty grasping onto moisture, once it latches on, it has an easier time retaining it.

For post-shower products, Blakely says to use a slip-enhancing detangler, so that you aren’t battling frizz. In general, Blakely suggests that those with lower porosity hair stick to lighter formulas and ingredients. “[This] promotes moisture without overwhelming the hair or leading to buildup,” says Blakely. Pro tip: Applying gentle heat from a warm towel can open up the cuticle and allow for better product absorption.

If you don’t know what ingredients you should be using, Rapier’s number one tip is to avoid silicone products that can be too heavy. Water-based formulas do a much better job of permeating the hair. Additionally, Rapier wants you to know that you should not overdo it with the proteins. “Low porosity hair can hold protein very well which can cause product buildup on your hair strands leaving them feeling dry and brittle,” she says. To prevent this, she says a weekly scalp and hair detox can melt it away.

What Is High Porosity Hair?

For those who most align with the features of high porosity hair, Rapier says that this is characterized by your cuticle being widely spaced out. This means you have less trouble with absorption, but more of a problem keeping it. Blakely says that high porosity is often the result of heat, chemical treatments, or environmental factors, so issues you may face include frizz, breakage, and dryness. As a healing measure, Blakely suggests swapping your regular leave-in for bond repair products like The Mane Choice Alpha Recoil Bond Repair Leave-In. This actively works to revitalize and protect your hair from damage while deeply penetrating for hydration.

When it comes to showering, this hair type requires more in-shower conditioning to maintain hydration levels. As a result, Blakely advises you to use products like the Mane Choice The Alpha Soft As Can Be Revitalize & Refresh 3-in-1 Co-Wash, Leave In, Detangler for a cleanse that is gentle, yet super moisturizing. On top of that, Rapier urges people with high porosity to regularly deep condition.

“Unlike low porosity hair, products with protein will actually be beneficial for high porosity hair,” says Rapier. She encourages the use of the V&Co. Beauty Wavy Hair Shampoo because it’s rich in proteins that can help reverse damage. Additionally, since our ends often face the most injury, she recommends layering light oils for extra moisture and split-end prevention. Plus, finding a gentle brush or comb can evade the harm that’s caused by rough detangling. Moreover, a general rule of thumb, Rapier says, is to avoid heat since high porosity hair is more prone to damage. So try to stay away from consistently reaching for your flat iron.